Abstract
The authors conducted the present study to elucidate the changes in cartilage rings with reference to abnormal bronchoscopic or bronchographic appearance of the tracheal mucosa.
On the postmortem male cases, whose age ranged between 15 to 80 years, obtained were clear soft roentgenograms of the tracheal ring, which were longitudinally incised to open it flat and were desiccated incompletely after dehydration in alcohol. These pictures of the rings were compared with the mucosal appearance.
1) Trachea consists of 16 to 20 pieces of rings, which lay in parallel with each other, demonstrating a zonal space between adjacent two rings (Type I space). Occasionally found was an ellipsoid-window-shaped space in a wide cartilage or a water-drop-shaped space at the bifurcation of two cartilages (Type II space). Frequently, a wide space of various shapes was present just above the carina. Numbers of the rings and shape of the spaces do not change with age.
2) Tracheal rings were 1500-7000 micra in width, showing no change with age
3) Mean thickness of the cartilage ring was 1258 micra on the young whose age ranged between 15 and 29 years and that in the aged, who was 60 to 80 years of age, was 1727 micra. Mean thickness for the young and that for the aged revealed significant difference (p<0.01).
4) Mean width of the space was 706 micra for the young while it was 1173 micra for the aged. Mean width of the space for these two groups revealed consistent difference (p<0.01). Mean width for the space of Type I was 845 micra and 1245 micra for the young and for the aged, respectively, showing consistent difference to each other. Mean width for the space of type II in the aged demonstrated skewed distribution.
5) Increase in the length of the trachea in the aged was evident. Among the aged deeper intercartilagenous grooves of the mucosa was found as a result of increased thickness of the rings.
6) Pin-point holes or small holes, which correspond to the openings of ducts of the mucosal gland, were found on the grooves. Pin-point holes were found in 40.0% and 85.5% of the grooves of type I in the young and in the aged, respectively (p<0.01), and in 48.0% and 68.4% of the grooves of type II (not significant). Prevalence of pin-point holes was significantly higher in type I grooves than in type II among the aged (p<0.05). The small hole was scanty and was found only in type II grooves in the young while this was also present in type I among the aged. There was a tendency that the small holes present in spaces of large width.
7) These holes were found frequently on the wide intercartilagenous space just above the carina.
